11/19/08

Some Common problems in system

Some Common problems in system

1. MONITOR LED IS BLINKING
Check all the connections like Monitor Cable, Data cables,RAM, Display Card , CPU connections.


2. CONTINUOS THREE BEEPS
Problem in RAM Connection.


3. THREE BEEPS ( 1 Long 2 Short)
Problem in Display Card Connection

4. THREE LONG BEEPS PERIOD WISE
Problem in BIOS or RAM (Basic Input Output System)


5. CONTINUOS NON-STOP BEEPING
Key Board Problem (I.e.; Some Key is pressed for Longer time)


6. FDD LED IS GLOWING CONTINUOSLY
Data cable to be connected properly (twisted cable).


7. NO DISPLAY ON THE SCREEN AT ALL
Hard Disk cable connected wrongly. Connect rightly seeing the Red mark (Faces power supply) and then Restart.


8. POWER LED IS OFF
a. Check main power cord
b. Check S.M.P.S.
c. Check Mother Board connection


9. SHOWING CMOS ERROR
Replace 3 Volt battery of Mother Board . Set Original Settings Manually.(Refer CMOS Setup chart)
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10. SHOWING FDD ERROR OR FLOPPY DRIVE IS NOT WORKING PROPERLY

Check Power cord of FDD , Data Cables , set CMOS & Finally the Check drive.


11. SHOWING HDD ERROR OR HARD DISK FAILURE
a. Check Power Cord
b. Check connection of HDD
c. Check Data cable
d. Check Hard Disk parameters in CMOS or Auto detecting Setting Partitions by Fdisk Command, then format it to set track 0.


12. MOTHER BOARD HANGS DUE TO UNSTABILIZED POWER SUPPLY
a. Check S.M.P.S
b. RAM not functioning properly.
c. Software problem (due to using pirated software)
d. CPU fan not functioning properly.


13. DANCING SCREEN
a. Check Display card connection
b. Virus Problem
c. Video Memory Problem


14. SHAKING SCREEN
a. Earthing problem
b. Magnetic waves comes around.


15. CPU CABINET SHOCK
a. Check Earthing
b. Check main power cord.


16. NON-SYSTEM DISK ERROR
a. Floppy Drive having different disk (Non-Bootable Disk) OR CMOS Parameters for Hard Disk may not be set properly.
b. Hard Disk Partitions may not be created.
c. Hard Disk may not be formatted.


7. MISSING OPERATING SYSTEM
The System files missing namely Ie; command.com} - User File IO.SYS & MS_DOS.SYS } - Hidden Files. These above three files required for Start up of the system that can be transferred by using SYS C: Command OR While the time of formatting by using Format c:/u/s


18. MISSING COMMAND INTERPRETOR
May the file Command.com is corrupted OR Infected by Virus OR Some one has Erased it.


19. SHOWING I/O ERROR
a. The type of Hard Disk in CMOS may not be set properly.
b. Operating system used for formatting is not valid


20. SHOWING DIVIDE OVER- FLOW MESSAGE
a. May some Directories or Files crash with other files.
b. Use CHKDSK/F or SCANDISK Command to correct it.


21. HARD DISK MAKING NOISE WHILE PROCESSING
a. Unstabilized power supply.
b. Check for Loose Contact.
c. Do not use Y Connectors for Hard Disk.
d. It may create Bad Sector OR Weak Hard Disk.


22. HARD DISK HANGS WHILE PROCESSING
Check for Bad Sector by using CHKDSK or SCANDISK Command. If found format the Hard Disk and set Partition before that area.(This is the only procedure to use Hard Disk with Bad Sector) OR (To avoid Bad Sectors use Standard Power Supply)


23. HARD DISK NOT DETECTED
a. Check Power Connector
b. Check Data Cables
c. Check Jumpers


24. PARTITION NOT SHOWN
Operating System where the Hard Disk formatted is not supported with present Mother Board. For Eg: Hard Disk formatted with Pentium System will hide their partitions for 486 System.


25. MMX/DLL FILE MISSING
May the above files may be corrupted due to power failure or Virus. Make available above files from other Computer. OR Reinstall Windows 98 Operating System. (This procedure will not make any effect on existing Data).


26. WINDOWS REGISTRY ERROR
This will happen due to sudden ON/OFF of the system. Final solution is to Reinstall Operating System.


27. DISPLAY COLOUR DOES NOT MATCH
a. Configure Display Card properly with their CD.
b. The Standard setting for Windows is set it to 800x600 for better performance.


28. UNKNOWN DEVICE FOUND
May the Driver utility is not provided with operating system . Insert Driver CD and install software for the above Device. (Every Device requires driver utility to set active)

A Brief Introduction Into TCP/IP

Many people may not know what TCP/IP is nor what its effect is on the Internet. The fact is, without TCP/IP there would be no Internet. And it is because of the American military that the Internet exists.During the days of the cold war, the defense department was interested in developing a means of electronic communication which could survive an attack by being able to re-route itself around any failed section of the network.They began a research project designed to connect many different networks, and many different types of hardware from various vendors. Thus was the birth of the Internet (sorta). In reality, they were forced to connect different types of hardware from various vendors because the different branches of the military used different hardware. Some used IBM, while others used Unisys or DEC.

TCP (Transmission Control Protocol) and IP (Internet Protocol) were the protocols they developed. The first Internet was a success because it delivered a few basic services that everyone needed: file transfer, electronic mail, and remote login to name a few. A user could also use the “internet” across a very large number of client and server systems.
As with other communications protocols, TCP/IP is composed of layers. Each layer has it’s own responsibility:

IP is responsible for moving data from computer to computer. IP forwards each packet based on a four-byte destination address (the IP number). IP uses gateways to help move data from point “a” to point “b”. Early gateways were responsible for finding routes for IP to follow.

TCP is responsible for ensuring correct delivery of data from computer to computer. Because data can be lost in the network, TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received.

How TCP/IP works

Computers are first connected to their Local Area Network (LAN). TCP/IP shares the LAN with other systems such as file servers, web servers and so on. The hardware connects via a network connection that has it’s own hard coded unique address – called a MAC (Media Access Control) address. The client is either assigned an address, or requests one from a server. Once the client has an address they can communicate, via IP, to the other clients on the network. As mentioned above, IP is used to send the data, while TCP verifies that it is sent correctly.

When a client wishes to connect to another computer outside the LAN, they generally go through a computer called a Gateway (mentioned above). The gateway’s job is to find and store routes to destinations. It does this through a series of broadcast messages sent to other gateways and servers nearest to it. They in turn could broadcast for a route. This procedure continues until a computer somewhere says “Oh yeah, I know how to get there.” This information is then relayed to the first gateway that now has a route the client can use.

How does the system know the data is correct?

As mentioned above, IP is responsible for getting the data there. TCP then takes over to verify it.

Encoded in the data packets is other data that is used to verify the packet. This data (a checksum, or mathematical representation of the packet) is confirmed by TCP and a confirmation is sent back to the sender.

This process of sending, receiving and acknowledging happens for each individual packet sent over the Internet.

When the data is verified, it is reassembled on the receiving computer. If a package is not verified, the sending computer will re-send it and wait for confirmation. This way both computers – both sending and receiving – know which data is correct and which isn’t.

One nice thing about this protocol is that it doesn’t need to stick to just one route. Generally, when you are sending or receiving data it is taking multiple routes to get to its destination. This ensures data accuracy.

Just the facts:

TCP/IP addresses are based on 4 octets of 8 bits each. Each octet represents a number between 0 and 255. So an IP address looks like: 111.222.333.444.

There are 3 classes of IP addresses:

Ranges starting with “1” and ending with “126” (i.e.. 1.1.1.1 to 126.255.255.254) are Class A

Ranges starting with “128” and ending with 191 (i.e.. 128.1.1.1 to 191.255.255.254) are Class B

Ranges starting with 192 and ending with 254 (i.e.. 192.1.1.1 to 254.255.255.254) are Class C ( You will notice that there are no IP addresses starting with “127”. These are reserved addresses.)

Calculating an IP address

One of the things that always confused me was how to convert IP address to their Binary form. It is quite simple really. IP addresses use the Binary numbers (“1”s and “0”s) and are read from right to left.

Each position in the binary address corresponds to a number, from 1 to 128 and look like this:

128 64 32 16 8 4 2 1

To calculate an address, simply add the numbers where a “1” appears.

For example, the following:

00001010 works out to 10. Like this:

0 0 0 0 1 0 1 0
128 64 32 16 8 4 2 1

You can see that the “1”s line up with the 2 and 8 – when you add 2 plus 8 the answer is 10.

Since an IP address contains 4 of these octets, it can be displayed in binary like:

00001010.00001010.00001010.00001010

Therefore, IP Address 10.129.254.1 would be converted to:

00001010.10000001.11111110.00000001
(8+2) . (128+1) .(128+64+32+8+4+2).(1)

While it’s not important for the average person to know how to figure this stuff out, it is important for someone setting up a small network. That is because TCP/IP also uses what are called subnet masks to determine which addresses are valid.

Wireless Internet Tips

If you plan on sharing your wireless Internet access, you will need to have that option turned on in your settings. However, if you do not have other computers hooked up to the network at this time, for security purposes, you should leave the setting turned off until the need arises to share the wireless Internet access.

Wireless Internet Speeds

Coming in at the slowest is Bluetooth, followed by 802.11b, 802.11a and topping the charts currently is 802.11g. 802.11b is roughly equivalent to the traditional wired 10BaseT Wired Ethernet networks. Therefore, switching to Wi-If should not considerably slow down your wireless Internet connection .

Wireless Network Equipment While Traveling

You will need to have a wireless network card, either an adapter or integrated in your laptop. If you do not have an available slot on your PC, there are adapters you can purchase that plug into a USB port on the computer.

Finding a Wireless Internet Hot Spot

There are several stores and restaurants that offer wireless Internet access, such as Starbucks. If you have a particular destination in mind, you can call the hotels to see if they offer the service. There are also hot spot directories that you can search to find wireless Internet access.

Wireless Internet - WiFi Standards

802.11 is the Wi-If standard, however there are other standards which are variations of the 802.11. These include:

* 802.11a
* 802.11b
* 802.11g
* 802.11i.

The differences among these standards includes speed, transmission frequency, and price. 802.11g is backwards compatible with previous products, but that is not the case with 802.11a. Make sure you check on compatibility issues prior to purchasing products.

Wireless Internet and Dial up

It is possible to share a wireless Internet connection with dial up, but it is not a very good idea. Some access points, such as the airport extreme base station from Apple, will allow this. However, there is some slow down time with sharing a wireless Internet connection, and if you decide to share a dial up connection, you won't be surfing anything fast.

Finding a Wireless Internet Hot Spot in a Chain

If you are traveling and know that you will be stopping at Starbucks, for example, and want to access the Internet, you can check out their website to see what specific franchises offer wireless Internet access.

Paying for Wireless Internet Access

Most likely, you will need to pay for the high speed wireless Internet access when you travel. Starbucks for example uses T-mobile as their wireless Internet provider. You will need to have a t-mobile account in order to access WI-if at Starbucks. There are some restaurants that may advertise free Wi-If, but in general, you should expect to pay a fee.

Nationwide Wireless Internet Service

There are a plethora of national wireless high speed Internet services available. AT&T, Sprint PCS, T-mobile, and Verizon are a few which offer nationwide service. You will want to check out various pricing, roaming policies and fees for the various networks.

Mixing Apples and PC's to Share Wireless Internet Connection

You can mix apple and PC on a wireless network and share a wireless Internet access. For example, Apple makes an access point called the AirPort Extreme Base station. Even though it is made by Apple, it still uses the Wi-If standard, and PC computers with a wireless adapter on the network will be able to share the wireless Internet connection

Mixing Wireless Internet and Wired Internet

You can easily share a wireless Internet access while still maintaining a wired network. There are many wireless routers on the market which offer both wired and wireless network capabilities. It is also possible to add on an access point after a wired router for wireless access.

Configuring Wireless Access Point to Share Wireless Internet Connection

Once you install the drivers on your computer for the access point, you will be able to open up the configuration software that comes with the router. The IP address 192.168.0.0 is the lowest in the network and should be dedicated to the router. Make sure to follow the specific configuration instructions that come with your wireless router, as each product will be slightly different from one another.

Wireless Internet Equipment

The beauty of the WI-FI is that it set a standard for wireless networking. Because of this, you do not need to have equipment from all the same venders in order to run a successful wireless network. You will be able to share wireless Internet access as well without having equipment from all the same venders.

Configuring Wireless Internet Card

You will need to use the configuration software that comes with your network card to configure your computer to work at various hot spots. Simply type in the hotspot network name (various depending on the service you are using) and state the type of network, such as access point. You can also scan available wireless broadband internet access in the area and choose which network you wish to connect with.

Wireless Internet WIFI

WI-FI, the 802.11 standard, is important for a variety of reasons. Having a standard in the industry ensures that anyone using wi-fi will be using the same standard, therefore equipment and connections are interchangeable. Having a set standard makes setting up wireless networks, sharing wireless internet access and working with wireless equipment more users friendly.